한반도에서 겨울철 지형성 구름에 대한 인공증설의 영향인자 분석

Abstract

During the period February to April 2010, twenty-five ground-based an AgI NH4I mixture burned in acetone, seeding experiments have been conducted over the Taebaek Mountains. Studies have been made on influence factor for snowfall augmentation by winter orographic cloud in Korean peninsula. We obtained the optimized conditions for the Daegwallyeong region as follows: surface temperature < 0℃, wind direction between 0 and 130°, wind speed < 5 m/s for at least 30 minutes. In order to get an appropriate AgI ratio for snowfall enhancement, we have been tested two seeding rate (SR1: 1.04 g min-1,SR2: 2.08 g min-1). As a results, eight out of twenty-five have been detected the enhancement of snowfall. It seems that the small AgI seeding (SR1) for snowfall augmentation is efficient for fall down. The case of the snowfall enhancement is as in the following: 1) Increment of snowfall appeared in the smaller seeding amount (SR1) except in exp. 15. 2) Even though easterly wind has observed at the Daegwallyeong region, snow enhancement only appears when the inflow of the easterly wind blew in toward Gangwon region from the East Sea. The simulations showed that the main reasons for the difference in snowfall augmentation by winter orographicd cloud as follows: The case of snowfall augmentation by seeding shows inflow of the easterly wind blew in toward Gangwon region from the East Sea with adequate supercooled liquid water. This suggests that the parcels absorbed an abundant amount of heat and moisture from the sea surface, and were modified from below while moving over the sea, leading to the occurrence of condensation in lower clouds. Results indicate that suitable conditions, such as wind field and supercooled liquid water, are needed for snowfall increment by seeding. The snow enhancement appears when 30-min averaged particle size measured by PARSIVEL disdrometer at Daegwallyeong before the start of burning is larger than 8 mm. Results indicate that suitable conditions, such as wind field and sufficient supercooled liquid water, are needed for snowfall increment by seeding.